Floral biology and reproductive system of Phaseolus augusti (Fabaceae)

HOC, P. S. & AMELA GARCÍA, M. T.

Beitrage zur Biologie der Pflanzen

Schraudolf, H., Vogel, S. & Weberling, F. Duncker & Humblot

Lugar: Berlin; Año: 1997 vol. 70 p. 121 - 140

Observations of floral morphology, anthesis, stigmatic receptivity, pollen viability, nectar, floral visitors, meteorological conditions and a self-compatibility experiment showed that: a) anthesis lasts 2 days and 3 floral phases occur, b) nectar secretion starts in opening buds and continues only during phase 1 (the most visited phase), c) nectar concentration fits that of melittophylous flowers, d) flowers are protandrous but the species is self-incompatible, d) rain or drizzle did not affect nectar concentration or poller viability but made pollinator visits diminish, e) the pollination unit is a flag-blossom that presents pollen on subapical stylar trichomes, f) the large and medium-sized hymenopterans Bombus atratus, B. opifex, Centris sp., C. bicolor and Megachile sp. were the most frequent pollinators, on which pollen was transferred on their heads or thorax dorsum, g) Bombus atratus, Centris sp. and Megachile sp. produce geitonogamy, so the rest of the pollinators were more effective in this disturbed comunity with few plants of P. augusti, h) the large bee Xylocopa eximia, various Lepidoptera and a hummingbird stole nectar.